1. Field of the Invention
The present invention relates to a new μ-oxo bridged heterometal naphthalo/naphthalocyanine compound which is useful for electric charge generating materials such as organic photoreceptors, photoconductive materials, optical recording materials, organic solar cell materials, nonlinear optical materials and the like, and to a production method thereof.
2. Description of the Related Art
Phthalocyanine-based compounds or naphthalocyanine-based compounds have been noted as organic photoconductive substances having sensitivity around a wavelength of 800 nm which is an oscillation wavelength range of a semiconductor laser. A number of organic photoreceptors (OPC) including such organic photoconductive substances as effective components have been proposed. For example, organic photoreceptors employing titanylphthalocyanine-based compounds as electric charge generating materials have been made to practical use.
Recently, medium-to-high sensitive electric charge generating materials provided with a new performance, that are suitable for the shortwaving of a light source by the prevalence of light-emitting diodes (LED) and OPC for color laser-beam printers (LBP), have been vigorously searched.
It has been known that phthalocyanine (Pc) compounds generate electric charge by irradiating and offer diverse electrical properties in accordance with polymorphs thereof, presence or absence, and kind of central metal thereof, and the like.
For example, with regard to a mixed crystal of two or more kinds of phthalocyanine compounds, Japanese Patent Laid-Open Publication No. H2(1990) 272067 discloses a production method of an X-type metal-free phthalocyanine composition, wherein the same quantity or less of titanylphthalocyanine as metal-free phthalocyanine is added to the metal-free phthalocyanine and, thereafter, crystal transformation is conducted by stirring. Japanese Patent Laid-Open Publication No. H4(1992) 351673 discloses a mixed crystal comprising oxytitanium phthalocyanine and at least one kind of hydroxymetal phthalocyanine. Japanese Patent Laid-Open Publication No. H4(1992) 184452 discloses an applying solution, which is used for photoreceptors, containing titanylphthalocyanine and a multilayer type phthalocyanine derivative. Japanese Patent Laid-Open Publication No. H8(1996) 67829 discloses a production method of a phthalocyanine mixed crystal, comprising: dissolving at least two kinds of phthalocyanine-based compounds in acid; and adding this solution to a mixture solution of water and an organic solvent having a dielectric constant of 20 or less so as to precipitate as the phthalocyanine mixed crystal. Japanese Patent Laid-Open Publication No. 2002-12790 discloses a mixed crystal comprising at least three kinds of phthalocyanine each having different central substance.
Further, Japanese Patent Laid-Open Publication No. H9(1997) 217020 discloses a μ-oxo aluminum phthalocyanine dimer having a new polymorph, and Japanese Patent Laid-Open Publication No. H10(1998) 88023 discloses a μ-oxo gallium phthalocyanine dimer. In addition, Japanese Patent Laid-Open Publication No. H7(1995) 295259 discloses an alkoxy bridged metal phthalocyanine dimer.
With regard to a μ-oxo heterometal phthalocyanine dimer, Japanese Patent Laid-Open Publication No. 2000-219817 discloses a μ-oxo aluminum/gallium phthalocyanine dimer. The phthalocyanine dimer described therein, however, is stochastically inevitably obtained as a mixture of three kinds which additionally contains a μ-oxo aluminum phthalocyanine dimer, a μ-oxo gallium phthalocyanine dimer.
Further, U.S. Pat. No. 4,900,817 discloses a polycyclic phthalocyanine compound such as (HO)GePc-O—SiPcOSi(C6H13)3. This polycyclic phthalocyanine compound, however, has tetravalent Si and Ge as central metal thereof. In addition, a production method thereof employs dehydration of hydroxy-substituted metal(IV) phthalocyanine in an organic solvent.